.getTriangle( @lineWidth, @height, @color, @dec) when not( @lineWidth = @height ) and ( @dec = 'top' )  {
    width: 0;
    height: 0;
    border-left: (@lineWidth/2) solid transparent;
    border-right: (@lineWidth/2) solid transparent;
    border-bottom: @height solid @color;
  }
 .getTriangle( @lineWidth, @height, @color, @dec) when not( @lineWidth = @height ) and( @dec = 'bottom' ){
    width: 0;
    height: 0;
    border-left: (@lineWidth/2) solid transparent;
    border-right: (@lineWidth/2) solid transparent;
    border-top: @height solid @color;
 }
 .getTriangle( @lineWidth, @height, @color, @dec) when not( @lineWidth = @height ) and( @dec = 'left' ){
    width: 0;
    height: 0;
    border-top: (@lineWidth/2) solid transparent;
    border-right: @height solid @color;
    border-bottom: (@lineWidth/2) solid transparent;
 }
 .getTriangle( @lineWidth, @height, @color, @dec) when not( @lineWidth = @height ) and( @dec = 'right' ){
    width: 0;
    height: 0;
    border-top: (@lineWidth/2) solid transparent;
    border-left: @height solid @color;
    border-bottom: (@lineWidth/2) solid transparent;
 }

 //渐变 做等边三角形需要    @height * 0.5 / 0.866 是三角形推导  底边 a = 右边 b * sin30 / sin60
.getTriangle( @lineWidth, @height, @color, @dec ) when ( @lineWidth = @height) and( @dec = 'top' ){
    width: 0;
    height: 0;
    border-left: (@height * 0.5 / 0.866) solid transparent;
    border-right: (@height * 0.5 / 0.866) solid transparent;
    border-bottom: @height solid @color;
 }
 .getTriangle( @lineWidth, @height, @color, @dec ) when ( @lineWidth = @height) and( @dec = 'bottom' ){
    width: 0;
    height: 0;
    border-left: (@height * 0.5 / 0.866) solid transparent;
    border-right: (@height * 0.5 / 0.866) solid transparent;
    border-top: @height solid @color;
 }
 .getTriangle( @lineWidth, @height, @color, @dec ) when ( @lineWidth = @height) and( @dec = 'left' ){
    width: 0;
    height: 0;
    border-top: (@height * 0.5 / 0.866) solid transparent;
    border-right: @height solid @color;
    border-bottom: (@height * 0.5 / 0.866) solid transparent;
 }
 .getTriangle( @lineWidth, @height, @color, @dec ) when ( @lineWidth = @height) and( @dec = 'right' ){
    width: 0;
    height: 0;
    border-top: (@height * 0.5 / 0.866) solid transparent;
    border-left: @height solid @color;
    border-bottom: (@height * 0.5 / 0.866) solid transparent;
 }



